Current drilling technology, including directional drilling technology, permits the drilling of conventional vertical wellbores which are substantially perpendicular to the ground surface, as well as deviated or non-vertical wellbores. Directional drilling technology also allows for branch, lateral or secondary wellbores to be drilled laterally from a main or primary wellbore. Lateral wellbores are often drilled and produced through a gap in the casing of the main wellbore. This gap typically comprises a window cut or milled in a section of the existing casing string. The lateral wellbore tends to extend laterally from the main wellbore to a desired location within the formation.
In order to drill and produce such lateral wellbores, it is necessary for downhole drilling and production tools to be capable of being located and oriented downhole. First, the downhole tool must be capable of being located at the desired depth beneath the surface. In particular, the downhole tool is preferably able to be located at or adjacent the window in the casing for the lateral wellbore. Second, in order that the tool may be diverted in the desired direction, such as for the drilling or re-entry of the lateral wellbore, the tool is also preferably able to be oriented within the wellbore in a desired direction.
Conventional downhole landing systems typically include one or more landing nipples spaced apart in a wellbore. These landing nipples provide internal profiled recesses which are compatible with the external profile of a corresponding lock mandrel or latch which is connectable to or forms a part of a downhole tool. Matching of the profiles on the landing nipple and the lock mandrel acts to locate the tool longitudinally within the wellbore at a desired location downhole. However, these conventional landing systems may not provide for or permit the downhole tool to be oriented in a desired manner relative to a lateral wellbore. Thus, these systems have limited application to the drilling or production of lateral wellbores.
For example, conventional downhole landing and locating systems are shown in U.S. Pat. No. 5,348,087 issued Sep. 20, 1994 to Williamson, Jr., U.S. Pat. No. 4,994,345 issued Jul. 31, 1990 to Mashaw Jr., U.S. Pat. No. 4,457,368 issued Jul. 3, 1984 to Knierimen et. al., U.S. Pat. No. 4,396,061 issued Aug. 2, 1983 to Tamplen et. al., U.S. Pat. No. 4,167,970 issued Sep. 18, 1979 to Cowan U.S. Pat. No. 4,164,977 issued Aug. 21, 1979 to Arendt et. al., and U.S. Pat. No. 4,023,620 issued May 17, 1977 to Gazda et. al.
As stated, it is important not only to be able to establish the depth of the downhole tool, but also to be able to establish an angular reference or orientation from which lateral wellbores may be drilled or selectively re-entered. U.S. Pat. No. 4,415,205 issued Nov. 15, 1983 to Rehm et. al. provides an indexing mechanism for both locating and orienting tools. More particularly, the indexing mechanism is comprised of an indexing dog which consists of a protrusion or internally projecting keys formed on the internal wall of the casing. The protrusion extends radially inwardly from the casing for engagement with an opening in a template associated with the downhole tool. These protrusions thus restrict the internal clearance or diameter of the casing and may therefore interfere with the work to be performed in the casing, as well as the tools which may be passed therethrough.
European Patent Application No. 0834643 published Apr. 8, 1998 also provides a method and apparatus for landing and orienting downhole tools at selected depths. More particularly, a well casing is provided with a plurality of landing and orienting joints located at selected depths. Each joint defines a differing internal landing profile and has a muleshoe therein. The muleshoe defines an upwardly facing point and an orientation slot and has helical guide ramp surfaces extending from the point to the orientation slot. The downhole tool incudes a plurality of landing dogs for engaging the landing profile of one of the joints. Further, the tool has an orientation key for guiding engagement with the helical guide ramp surfaces and orienting engagement with the orientation slot. Thus, a relatively complex structure is provided for landing and orienting the tool. Further, the structure provided for landing the tool is distinct or separate from the structure provided for orienting the tool.
U.S. Pat. No. 5,579,829 issued Dec. 3, 1996 to Comeau et. al. provides a keyless latch assembly having external surface contours compatible with a recessed area formed on the internal surface of a well casing. The recessed area is comprised of a series of grooves and slots for receiving the latch assembly therein. More particularly, upon the alignment of the latch assembly longitudinally with the grooves, the latch assembly is located at a desired depth beneath the surface. Upon the further alignment of the latch assembly rotationally with the slots, the latch assembly is oriented in a desired direction.
However, the latch assembly and grooves permit the latch assembly to be moved longitudinally in either an upwards or a downwards direction within the casing upon the application of further force to the latch assembly to overcome the engagement of the latch assembly with the grooves. Only upon the rotational alignment of the latch assembly with the slots is the latch assembly prevented from moving longitudinally in a downwards direction away from the surface. Thus, it is possible that a downhole tool fitted with the latch assembly could be accidentally dropped or pushed through the recessed area, and lost downhole, in the event the latch assembly passes through the recessed area without aligning with the slots.
Therefore, there is a need in the industry for a fail-safe or safety apparatus for longitudinally supporting and rotationally orienting a well tool in a wellbore at a location beneath the surface. Further, there is a need for a fail-safe or safety tubular receiving member for use in combination with a latch assembly to longitudinally support and rotationally orient the latch assembly in the wellbore. More particularly, there is a need for the apparatus and the receiving member to prevent the longitudinal movement of a latch assembly relative to the receiving member in a downward direction away from the surface, such that a tool fitted with the latch assembly may be located at a desired depth downhole and may not be accidentally lost downhole, while still permitting the latch assembly, and the tool connected therewith, to be oriented in a desired direction.